基于半正定规划的低压不对称配电网储能优化方法

高渗透率分布式电源的不对称接入加剧了有源配电网的电压波动,使得有源配电网的三相不平衡问题更加突出,导致配电网中设备的损耗增加并处于不正常运行状态,给系统的安全运行带来风险。为此,提出了一种基于储能系统的有源配电网不对称运行优化方法,通过调节储能系统的运行策略,提高系统运行的经济性,并改善有源配电网运行中的三相不平衡程度。通过引入线性化和凸松弛技术,将原本非凸非线性的优化模型变为半正定模型,降低了优化问题的求解难度,提高了求解效率;最后,基于改进的IEEE 123节点系统验证了所提方法的正确性和有效性,通过调节储能的运行策略,减小了三相配电系统不对称运行损耗和电压波动。

Optimal Method for Energy Storage System in Low-voltage Asymmetric Distribution Networks Based on Semi-definite Programming

The asymmetric integration of distributed generations(DGs)with high penetration rate exacerbates the volt?age fluctuations in active distribution networks(ADNs),which makes the three-phase unbalance problem in ADNs more predominant.As a result,the loss of equipment in the distribution network increases and the equipment operates in abnormal conditions,causing security risks to the system operation.In this paper,an energy storage system(ESS)-based optimal method is proposed for the asymmetric operation of ADNs.By regulating the operation strategy for ESS,the economic efficiency of system operation is improved and the three-phase unbalance index for ADN operation is miti?gated.Through the introduction of linearity and convex relaxation technique,the original non-convex,nonlinear optimi?zation model is converted into a semi-definite programming(SDP)formulation,which reduces the difficulty in solving the optimization problem and improves the corresponding efficiency.Finally,a case study is performed on a modified IEEE 123-node system,which verifies the validity and effectiveness of the proposed method,i.e.,by regulating the op?eration strategy for ESS,the unbalance operation loss and voltage fluctuations of the three-phase distribution system can be reduced.